Cystatin C Turbidimetric Immunoassay Kit
Human cystatin C (or cystatin 3), which is composed of 120 amino acid residues, belongs to the cystatins superfamily that inactivates lysosomal cysteine proteinases. As a strongly cationic and low-molecular weight (13.4 kDa) protein, it is almost freely filtered across the glomerular membrane, and is therefore used as a biomarker of kidney function. A growing body of evidence suggests that cystatin C is a more reliable biomarker of glomerular filtration rate than creatinine. The normal range of Cystatin C in plasma sample is 0.5 – 10.3 mg/L. In addition to kidney disease, altered serum levels of cystatin C are associated with several types of cardiovascular disease, including myocardial infarction, stroke, heart failure, peripheral arterial disease and metabolic syndrome.
IMD developed its cystatin C PETIA kit with excellent reproducibility and accuracy equivalent to FDA-approved assays.
PRINCIPLE OF THE ASSAY
This assay is a turbidimetric immunoassay for the quantitative measurement of Cystatin C in human serum, plasma and urine. A standard or sample is added into a cuvette and mixed with the reaction buffer R1. After a short incubation, the test reagent R2, which is a suspension of microparticles coated with Cystatin C antibodies, is added into the cuvette and mixed. The presence of Cystatin C in the standard or sample causes the immune-particles to aggregate. The extent to which the microparticles aggregate is quantified by the amount of light scattering measured as absorbance by a chemistry analyzer. The concentration of Cystatin C in unknown samples can be interpolated from a reference curve using the standards provided.
PERFORMANCE OF THE KIT
TYPICAL STANDARD CURVE
Cystatin C (mg/L)
Absorbance (570 nm)
Assay procedures may vary depending on the automated chemistry analyzer to be used. A general example of assay procedures is stated as follow:
1. Dispense 150µl of R1 into a clean cuvette
2. Add 1.5µl of sample and incubate at 37˚C for 5 minutes
3. Further add 50µl of R2
4. Read change of absorbance at 570 nm for 8 minutes after the addition of R2
5. Calculate the concentration of Cystatin C in unknown sample by interpolation from a reference curve using the standards provided
R1: 15ml, R2: 5ml
R1: 30ml, R2: 10ml
R1: 60ml, R2: 20ml
R1: 150ml, R2: 50ml
R1: 300ml, R2: 100ml
For bulk order, please enquire